1. Field of the Invention
The present invention relates to a flash disaster recovery system and more particularly to a flash disaster recovery system for enabling a computer system to recover from incorrect or interrupted programming of a flash memory device by way of external hardware manipulation of the flash memory address in order to enable the system to be rebooted from the boot block area and thus enable reprogramming of the flash memory device by way of a serial port.
2. Description of the Prior Art
Flash disaster recovery systems are known. In such systems, the basic input/output system (BIOS) is normally provided on a flash memory device to enable the BIOS to be easily updated. Prior to the utilization of flash memory devices, the BIOS was normally written in a read only memory (ROM). In systems where the BIOS is contained in a ROM, updating of the BIOS required that the ROM be replaced. In order to obviate the need to replace the ROM or updates in the BIOS, flash memory devices are used. Such flash memory devices enable the BIOS to be rather easily updated. Unfortunately, if a problem occurs during the programming of the flash memory device, the system will not be able to be rebooted. In such situations, an alternate method for rebooting the computer is provided during such conditions. For example, U.S. patent application Ser. No. 07/885,805, filed on May 15, 1992 and assigned to the same assignee as the assignee of the present invention, discloses a computer system which includes a flash memory device for storing the BIOS. In order to enable the system to be rebooted in the event of a flash disaster, a special-purpose parallel port is provided. The special-purpose parallel port switches from a standard peripheral interface mode to a special-purpose interface when the flash memory device becomes corrupted. In the special-purpose interface mode, the parallel port enables the BIOS to be executed from an external ROM or another personal computer. However, the special-purpose parallel port complicates the system as well as increases the cost. U.S. patent application Ser. No. 08/469,206, filed on Jun. 6, 1995, also assigned to the same assignee as the assignee for the present invention, also relates to a computer system which utilizes flash ROM for BIOS. In this system the BIOS initialization functions are stored in the boot lock or protected area of the flash memory device in order to enable the flash memory device to be reprogrammed when the data becomes corrupt.